One of ours loves to eat them.  Needless to sat we try to stop him but
with a live (real) tree in the house it is kind of hard to keep him
from doing it!!  He like the green ones.  When we see the tree wiggle
it is a give away that someone is pulling the needles off.

With an open floor plan it is hard to keep him away from it when no
one is home during the work day!!

Billy U has brought this to us :

The only thing to be wary of is if they have been sprayed with some
type of chemical.  I think this is done to give them greater
durability.  My cats come in smelling of pine needles as they border my
property.